This invention relates to a tool-changing apparatus or device for a multiple-spindle milling machine with a gantry covering the working-part table at which the individual working spindles are movable from their working position side by side at the same time in a tool-change position sideways from the working-part table, and with a tool-storage unit arranged on the same side of the working-part table near the milling machine, on which tools or tool-pickup devices to be changed are kept ready at a delivery station, and with tool-gripping devices movable between this delivery station and the working spindles in tool-change position, among which each gripping device is turnable and is arranged in the change position of each of the working spindles.
Such a tool-changing device is known from U.S. Pat. No. 3,571,912. With this known tool-changing device, it was also possible already to change the tools of all working spindles of multiple-spindle milling machines at the same time. For this purpose, the tool-gripping devices which successively remove the tool to be replaced from the working spindle and insert the new tool into the pickup of the working spindle are arranged in a common carrier on which the tool-gripping devices are fixed in the interval of the working spindles.
This arrangement of the tool-gripping devices entails several disadvantages. In the case of large working parts to be worked at the same time, the working spindles have a considerable spacing. The spacings of the tool-gripping devices on the tool-changing device must be of equal size. However, the dimensions of the tool-storage unit, at whose delivery station the tools to be taken or the tool-pickup devices to be kept in readiness must be arranged at the same spacing, are also governed in this way. In the known design, the tool-changing device in delivery position at the tool-storage unit can only remove or deposit tools from the tool-pickup devices simultaneously with all the tool-gripping devices. Consequently, the fact that it is not possible to vary the spacings of the working spindles is a special disadvantage of this known machine.
In order to overcome these disadvantages, the goal of the invention was that of designing a tool-changing device of this type so that as much freedom as possible exists in selecting the tool interval for a plane in the tool-storage unit, which must simultaneously be kept ready at all working spindles for each tool-changing process.